Field of the Disclosure
The present invention relates to wireless communications, and more particularly, to a method and apparatus for transmitting uplink control information in a multi-carrier system.
Description of the Related Art
Standardization works of international mobile telecommunication (IMT)-advanced which is a next generation (i.e., post 3rd generation) mobile communication system are carried out in the international telecommunication union radio communication sector (ITU-R). The IMT-advanced aims at support of an Internet protocol (IP)-based multimedia service with a data transfer rate of 1 Gbps in a stationary or slowly moving state or 100 Mbps in a fast moving state.
3rd generation partnership project (3GPP) is a system standard satisfying requirements of the IMT-advanced, and prepares LTE-advanced (LTE-A) which is an improved version of long term evolution (LTE) based on orthogonal frequency division multiple access (OFDMA)/single carrier-frequency division multiple access (SC-FDMA) transmission. The LTE-A is one of promising candidates for the IMT-advanced.
Carrier aggregation (CA) is one of candidate techniques to be used in LTE-A. The CA is a technique capable of configuring a broadband by aggregating multiple narrowband component carriers (CCs). In a wireless communication system using the CA, multiple control information can be transmitted through one uplink CC. For example, when acknowledgement/not-acknowledgement (ACK/NACK) for data transmitted through each of multiple downlink CCs is transmitted through one uplink CC, there may be a case where multiple ACK/NACKs must be transmitted. That is, unlike the conventional single-carrier system, the multi-carrier system may occasionally have to transmit multiple control information.
Accordingly, there is a need for a method and apparatus for transmitting uplink control information in a multi-carrier system.